Update ignore files

.gitignore

@@ -1,9 +1,43 @@
-*.iml
-.gradle
-/local.properties
-/.idea/workspace.xml
-/.idea/libraries
-.DS_Store
-/build
 /captures
 .externalNativeBuild
+
+## https://gist.github.com/iainconnor/8605514
+
+# Built application files
+/build
+/*/build/
+
+# Crashlytics configuations
+com_crashlytics_export_strings.xml
+
+# Local configuration file (sdk path, etc)
+local.properties
+
+# Gradle generated files
+.gradle/
+
+# Signing files
+.signing/
+
+# User-specific configurations
+.idea/copyright/profiles_settings.xml
+.idea/libraries/
+.idea/.name
+.idea/compiler.xml
+.idea/encodings.xml
+.idea/misc.xml
+.idea/modules.xml
+.idea/scopes/scope_settings.xml
+.idea/tasks.xml
+.idea/vcs.xml
+.idea/workspace.xml
+*.iml
+
+# OS-specific files
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db